Note: Descriptions are shown in the official language in which they were submitted.
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Actuator For Delivery Of Vibratory Stimulation
To An Area Of The Body And Method Of Application
CROSS-REFERENCES TO RELATED APPLICATIONS
[0001] This application claims priority from U.S. Patent Application
No. 61/445,629
filed February 23, 2011.
STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH
[0002] Not Applicable.
BACKGROUND OF THE INVENTION
1. Field of the Invention
[0003] This invention relates to a method and apparatus for delivering
local and/or
regional vibrations to a body tissue. In particular, the present invention
relates to an
actuator for delivery of linear mechanical vibrations to a body tissue that
may
comprise skin tissue, muscle tissue, glands, fibrous tissue, bone tissue and
internal
organs, including the brain ¨ in humans as well as in animals and veterinary
applications.
2. Description of the Related Art
[0004] The application of vibrations as a therapeutic modality was
practiced in
different forms throughout history. Today vibration therapy is an emerging
treatment
modality used in sports medicine, orthopedics, rehabilitation medicine,
neurological
conditions, wound healing, pain alleviation, sensory enhancement and many
other
fields of medicine (Merkert J, Butz S, Nieczaj R, Steinhagen-Thiessen E,
Eckardt R.
Combined whole body vibration and balance training using Vibrosphere(R):
improvement of trunk stability, muscle tone, and postural control in stroke
patients
during early geriatric rehabilitation. Z Gerontol Geriatr 2011;44:256-61;
Leduc A,
Lievens P, Dewald J. The influence of multidirectional vibrations on wound
healing
and on regeneration of blood- and lymph vessels. Lymphology 1981;14:179-85;
King
LK, Almeida QJ, Ahonen H. Short-term effects of vibration therapy on motor
impairments in Parkinson's disease. NeuroRehabilitation 2009;25:297-306; Arias
P,
Chouza M, Vivas J, Cudeiro J. Effect of whole body vibration in Parkinson's
disease:
a controlled study. Mov Disord 2009;24:891-8; Kakigi R, Shibasaki H.
Mechanisms of
pain relief by vibration and movement. J Neurol Neurosurg Psychiatry
1992;55:282-6;
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Magalhaes FH, Kohn AF. Vibratory noise to the fingertip enhances balance
improvement associated with light touch. Exp Brain Res 2011;209:139-51;
Johnson
AW, Myrer JW, Hunter I, et al. Whole-body vibration strengthening compared to
traditional strengthening during physical therapy in individuals with total
knee
arthroplasty. Physiother Theory Pract 2010;26:215-25; Adatto M, Adatto-Neilson
R,
Servant JJ, Vester J, Novak P, Krotz A. Controlled, randomized study
evaluating the
effects of treating cellulite with AWT/EPAT. J Cosmet Laser Ther 2010;12:176-
82;
Ozcivici E, Luu YK, Rubin CT, Judex S. Low-level vibrations retain bone
marrow's
osteogenic potential and augment recovery of trabecular bone during
reambulation.
PLoS One 2010;5:e11178; Xie L, Jacobson JM, Choi ES, et al. Low-level
mechanical
vibrations can influence bone resorption and bone formation in the growing
skeleton.
Bone 2006;39:1059-66; Jobges EM, Elek J, Rollnik JD, Dengler R, Wolf W.
Vibratory
proprioceptive stimulation affects Parkinsonian tremor. Parkinsonism Relat
Disord
2002;8:171-6.)
[0005] Vibratory stimulation of tissues when applied externally or
internally can be
beneficial for different applications including, but not limited to: tissue
perfusion,
tissue oxygenation, pain alleviation, muscle injuries, bone injuries,
enhancement of
bone growth, enhancement of cartilage growth, tissue repair and/or tissue
regeneration, inflammation, balance dysfunction, erectile dysfunction,
neuropathy,
sleep disorders, chronic and other wounds such as pressure ulcers, venous
ulcers,
arterial ulcers, and diabetic ulcers, burns, surgical wounds, dehisced wounds,
preventive treatment for pressure ulcers, transdermal drug delivery,
osteoporosis,
cellulite removal, neurological conditions, Parkinson's disease tremor
reduction,
fibromyalgia, veterinary use, and other therapeutic uses.
[0006] Several devices have been proposed which deliver vibration to the
tissue.
These devices use different methods for the delivery of vibratory energy to
the skin
which include rotating asymmetric motors, linear motors, pneumatic devices,
transducer materials, piezoelectric foils, voice coil and piezoelectric
actuators. See,
for example, PCT International Patent Application Publication Nos. WO 99/48621
and
WO 2010/093753, U.S. Patent Application Publication Nos. 2004/0030267 and
2007/0208280, and U.S. Patent No. 7,211,060.
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[0007] Piezoelectric actuators are being used for the delivery of
linear (as
opposed to rotating asymmetric motors) vibratory energy to the body,
particularly in
applications such as ultrasound, where high frequency (10kHz-30kHz), low
amplitude
vibrations are required. Piezoelectric materials exhibit electromechanical
interaction
between the mechanical and the electrical states. When an electrical field is
applied
to a piezoelectric material, it induces a mechanical strain. The mechanical
strain in
the piezoelectric actuator is directly or indirectly translated into
movement..
[0008] The use of piezoelectric actuators for the delivery of
mechanical vibratory
energy to a body tissue is limited for several reasons:
[0009] First, driving the piezoelectric actuator typically requires high
voltages.
[0010] Second, the piezoelectric material must be protected from
liquids such as
water, sweat, wound exudates, and other bodily or non-bodily liquids that may
come
in touch with an electric element.
[0011] Third, the piezoelectric actuator must be held in place tight
against the
tissue, preferably having direct contact with the skin or through an adhesive
layer or
gel such that the vibratory energy is delivered to the tissue. The skin-
attachment
mechanism must provide good mechanical coupling to facilitate efficient
transmission
of the vibratory energy into the tissue. Having a breathable skin-attachment
mechanism is preferable in order to preserve skin health during the length of
use.
[0012] Fourth, piezoelectric elements are in many cases fragile and
brittle; they
break easily and partially or completely lose functionality when exposed to
mechanical load. The piezoelectric actuator must have mechanical properties
that
will allow it to resist pressure from the tissue and various other mechanical
loads /
stresses that result from body-attachment applications.
[0013] Fifth, under mechanical loads the amplitude (travel) of the
piezoelectric
element is dampened and may be limited. The piezoelectric element must have
some free space (air gap) on at least one side of it to develop proper
vibratory modes
and amplitudes.
[0014] What is needed therefore is a method and device for delivering
vibratory
stimulation to a part of the body using a piezoelectric element that is
insulated from
the tissue, protected from liquids, has improved resistance to mechanical
failure, can
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develop the desired vibratory modes and amplitudes, and has good mechanical
coupling with the body surface (skin or other).
SUMMARY OF THE INVENTION
[0015] The present invention meets these needs and requirements by providing a
method and a device for delivering vibratory stimulation to a part of the body
using a
piezoelectric element that is packaged in a polymer such that the
piezoelectric
element is insulated from the tissue, protected from liquids, has improved
resistance
to mechanical failure, and can come in direct contact with the skin without
risk of
electric shock. The polymer packaging, in addition to protecting the
piezoelectric
element from mechanical damage, also acts to help maintain complete or near-
complete piezoelectric actuation even in the presence of cracks, fractures,
and other
mechanical defects in the piezoelectric element.
[0016] Packaging may also include one or more surface electrodes for the
actuation of the piezoelectric element, each electrode covering part or all of
a surface
area of the piezoelectric element. The purpose of such electrodes is to
maintain
complete or near-complete piezoelectric actuation even in the presence of
cracks,
fractures and other mechanical defects in the piezoelectric element.
[0017] The actuator described in the present invention can be connected by an
electrical lead or wirelessly to a controller unit which controls the
electrical signal
and/or power delivered to the actuator. In some embodiments, there is more
than
one actuator connected to the same controller unit.
[0018]
Therefore, in one aspect the invention provides an actuator for delivering
mechanical vibrations to the body of a subject (e.g., human or other mammal).
The
actuator includes one or more piezoelectric elements, electrodes in electrical
communication with a power source and the piezoelectric element to drive the
piezoelectric element, a protective layer encapsulating the piezoelectric
element and
at least part of the electrodes wherein the protective layer comprises a
polymeric
material, and an enclosure attached to the protective layer wherein the
enclosure
defines a space between the protective layer and the enclosure allowing
desired
modes of vibration to develop across a surface of the protective layer which
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encapsulates the piezoelectric element. The polymer-packaged piezoelectric
element includes the piezoelectric element, the electrodes, and the protective
layer.
[0019] The electrodes may be separated from the protective layer
and be an
independent part or they may be part of the protective layer by being for
example
laminated to the protective layer. A typical construction of polyimide-copper
laminate
includes a polyimide base film used as an electrically insulating base
material, a thin
metal tiecoat (chromium or nickel based alloy, which serves to enhance
adhesion), a
copper seed-coat, and a layer of electrodeposited copper. Such configuration
could
be, for example, single or double sided copper clad, flexible adhesive free
polyimide
dielectric laminates. Available polyimide dielectric laminates include for
example
DuPontTM Kapton , DuPontim Kapton HN, DuPontTM Pyraluxe AC, DuPontTm
Pyralux AP and DuPontTM Interra TM HK.
[0020] The protective layer and electrodes may be attached to the
piezoelectric
element using a glue such as an epoxy glue. Pressure may be applied while
attaching the protective layer, electrodes and piezoelectric element to ensure
good
contact of the electrodes with the piezoelectric element. If a glue such as an
epoxy
glue is used for attaching the protective layer and electrodes to the
piezoelectric
element, heat may be applied in order to enhance curing of the glue.
Alternatively
other glues such as acrylic based glues can be used.
[0021] In one form of
the present invention, the polymer-packaged piezoelectric
element is shaped as a flat disc and is fixed to the rigid or semi-rigid
enclosure such
that the perimeter of the polymer-packaged piezoelectric element is affixed to
the
perimeter of the enclosure, thus providing mechanical lip-conditions
(preventing/minimizing motion of the polymer-packaged piezoelectric element at
the
perimeter) and allowing a diaphragm-like movement at the center of the
circular
polymer-packaged piezoelectric element. The enclosure also provides free-space
on
one side of the polymer-packaged piezoelectric element (preferably the side
far away
from the skin), so that desired vibratory modes and desired amplitudes can
develop
across the surface of the polymer-packaged piezoelectric element.
[0022] In some embodiments, the polymer-packaged piezoelectric element and
the enclosure are connected only partially along certain sections of the
perimeter,
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thus providing different lip-conditions resulting in various vibratory modes
developing
across the surface of the polymer-packaged piezoelectric element.
[0023] In some embodiments, the polymer-packaged piezoelectric element and
the enclosure have shapes other than circular, and are attached to one another
fully
or only partially along the entire lip or only along certain sections of the
lip.
[0024] In one embodiment, the enclosure contains a ventilation outlet
allowing
passage of gasses into and out of the enclosure such that pressure or vacuum
do not
build up in the enclosure during actuation.
[0025] In some embodiments, the polymer-packaged piezoelectric element can be
used as an actuator without the enclosure and then the vibrations will have
different
distribution over the polymer-packaged piezoelectric element surface.
[0026] In some embodiments the surface of the polymer-packaged piezoelectric
element on the side facing the skin is textured to produce a different
mechanical
stimulation of the skin. Such texture can be for example a grid of bubble
shaped
bodies that will cover the surface of the polymer-packaged piezoelectric
element.
[0027] In some embodiments, the enclosure is open in both sides. For
example,
in the case of a circular polymer-packaged piezoelectric element, the
enclosure will
have the shape of an open ring.
[0028] In some embodiments, the polymer-packaged piezoelectric element
contains one piezoelectric element, two piezoelectric elements, or a stack of
more
than two piezoelectric elements. When more than one piezoelectric element is
used,
an electrode can be placed between piezoelectric elements - for example a
single
electrode or a double sided copper clad, flexible adhesive free polyimide
dielectric
laminate.
[0029] The piezoelectric element(s) can be packaged in the protective layer
using
polyimide or other materials including polyetherketones,
polyetheretherketones,
polybenzimidazoles, polyphenylensultides, silicone, polyamidimides,
polysulfones,
polyethersulfones, liquid crystalline polymers, or combinations thereof. In
addition,
more than one layer of polymer can be used where different polymers are used
in
each layer.
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[0030] In another aspect, the invention provides a skin attachment
mechanism for
attaching the actuator to the skin of the subject. In one embodiment, the skin
attachment article includes a cover, a mounting pad, a connecting strip
flexibly
connecting the mounting pad and the cover, and a first adhesive layer for
attaching
the article to skin of a subject with the mounting pad contacting the skin and
the
cover overlying the mounting pad such that an outer perimeter of the cover is
spaced
outward from an outer perimeter of the mounting pad.
[0031] In one embodiment, the actuator is attached to the skin by
means of a
double sided adhesive layer or gel such that the actuator is delivering the
vibrations
to the skin through the adhesive layer or gel. In another embodiment, the
actuator is
placed directly over the skin and fixed to the skin using a fixation method
such as
adhesive tape, strap or other fixation method that is applied over the
actuator.
[0032] The edges of the polymer-packaged piezoelectric element and/or the
edges of the enclosure may be tapered, beveled, rounded or otherwise modified
as
to minimize potential damage to the skin, underlying tissue, or fixation
method
(adhesive or other) that attaches the actuator to the skin.
[0033] The actuation frequencies used with the actuator can range from 1 Hz to
4
kHz. Preferred actuation frequencies for use in therapeutic applications that
are not
ultrasonic, ranges from 1 Hz to 500 Hz, and in some embodiments, from 5 Hz to
100
Hz. Preferred actuation amplitudes for use in stimulation of tissue response
in
therapeutic applications ranges from 0.001 millimeters to 3 millimeter peak-to-
peak.
[0034] In one embodiment, the actuator of this invention is attached
to the skin
using an adhesive-based attachment system. This system contains three
components. The first component is a double sided adhesive mounting pad that
is
attached to the skin on one side and the actuator is attached to the opposite
side with
the actuator facing the skin. The mounting pad can be made of woven, nonwoven
or
hydrogel materials, as well as other types of gel, foam or film. The mounting
pad can
be breathable or not breathable and in some embodiments, it can be perforated.
[0035] The second component of the adhesive-based attachment system is a top
cover larger in perimeter size than the actuator and mounting pad, that covers
the
actuator fully or partially to reinforce the attachment of the actuator to the
skin. In
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one embodiment, the top cover is made of flexible material that will conform
to the
shape of the actuator and will fasten the actuator to the skin by applying
pressure
over the actuator. Such flexible material can be woven, non-woven or made of
foams, films, gels, or layers such as polyurethane, polyethylene or polyvinyl
chloride.
The top cover can be breathable or not breathable and in some embodiments, it
can
be perforated.
[0036] The third component of the adhesive-based attachment system is a
connecting strip in the form of an adhesive double sided strip that connects
the
mounting pad and the top cover. The connecting strip can help hold the double-
sided mounting pad and top cover in the right position allowing easy
positioning of
the top cover over the actuator. In some embodiments, the connecting strip can
be
an integral part of the mounting pad or the top cover. In some embodiments,
the
connecting strip can be coated with adhesive on the skin side or both sides
thereby
positioning the adhesive patch folding point. In some embodiments, the
connecting
strip has no adhesive. In one embodiment, the connecting strip is not included
and
the double-sided mounting pad and the top cover are provided as two separate
units.
[0037] In another embodiment, there is a pressure-relief apparatus
added to the
attachment system, for example in the form of a foam ring that fits around the
outside
perimeter of the actuator.
[0038] In some embodiments, the actuator can be used over healthy tissue to
stimulate vascular response that will for example be anti-thrombotic. Such use
can
be for example delivery of vibrations during medical procedures that have risk
of
thrombosis or long sitting time such as during travel. Vibrations can promote
blood
flow thereby induce fibrinolysis and reduce the risk of thrombosis.
[0039] In one aspect the invention provides an actuator for delivering
mechanical
vibrations to the body of a subject. The actuator includes a piezoelectric
element,
electrodes in electrical or wireless communication with a power source and/or
a
signal source and the piezoelectric element to drive the piezoelectric
element, a
protective layer encapsulating the piezoelectric element and at least part of
the
electrodes, the protective layer comprising a polymeric material, and an
enclosure
attached to the protective layer and defining a space between the protective
layer
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and the enclosure allowing desired modes of vibration to develop across a
surface of
the protective layer. In one form, a perimeter of the protective layer is
affixed to a
perimeter of the enclosure thus providing mechanical lip-conditions that
prevent
and/or minimize motion of the piezoelectric element at its perimeter. In one
form, the
protective layer and the enclosure are affixed only partially along certain
sections of
the perimeter of the protective layer and the perimeter of the enclosure. The
enclosure can include a ventilation outlet. In one form, an outer perimeter of
the
protective layer is spaced outward from an outer perimeter of the
piezoelectric
element. The actuator can include one or more additional piezoelectric
elements
encapsulated in protective layers.
[0040] The actuator can transmit vibrations to skin or other body
tissue of the
subject when the actuator is placed on the skin or other body tissue with the
protective layer facing the body either directly or through an intermediate
layer and
when electrical signals are delivered to the piezoelectric element from a
control unit.
In one form, the polymeric material is selected from polyimides,
polyetherketones,
polyetheretherketones, polybenzimidazoles, polyphenylensulfides, silicones,
polyamidimides, polysulfones, polyethersulfones, liquid crystalline polymers
or
combinations thereof. The protective layer can be polymerized on the
piezoelectric
element. The protective layer can be a sheet laminated or glued to the
piezoelectric
element, and the laminated or glued sheet includes the electrodes that will
deliver
electric signal to the piezoelectric element. The polymeric material can be
selected
from polyimides. The protective layer can be surrounded by a pressure-relief
apparatus. The enclosure can include opposed open ends. In one form, the
actuator
is not attached to an enclosure. In one form, the piezoelectric element
comprises a
lead zirconate titanate. The edges of the enclosure can be tapered, beveled,
or
rounded, and/or edges of the protective layer can be tapered, beveled, or
rounded.
The actuation frequencies for the piezoelectric element can range from 1 Hz to
4
kHz. The actuation amplitudes for the piezoelectric element can range from
0.001
millimeters to 3 millimeter peak-to-peak. In one form, a surface of the
protective layer
is not smooth and has a texture to enhance a stimulatory effect. In one form,
a
diameter of the protective layer is bigger than a diameter of the
piezoelectric element.
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[0041] The actuator can include a sensor in electrical or wireless
communications
with a power source and/or a signal source and/or the piezoelectric element,
such
that that input from the sensor modifies the power and/or signal from the
source to
the piezoelectric element or modifies the response of the piezoelectric
element to
such power or signals from the source. The sensor can be selected from
perfusion
sensors, oxygenation sensors, piezo-film sensors, temperature sensors,
photoplethysmographic sensors, strain-gauge plethysmography sensors, laser-
Doppler sensors, laser-speckle sensors, infrared imaging, infrared
spectography,
ultrasound sensors, motion sensors, strain sensors, pressure sensors, and
vibration
sensors.
[0042] The actuator can further include: at least one of: devices for
applying
negative pressure below or around or adjacent to the actuator, hyperbaric
oxygen
devices, compression devices, shockwave devices, heating devices, cooling
devices,
light-emitting devices, ultrasound devices, electromagnetic stimulation
devices,
electrical current stimulation devices and wound dressings. The actuator can
be
used for increase in tissue perfusion, increase in tissue oxygenation, pain
alleviation,
muscle injuries, bone injuries, enhancement of bone growth, enhancement of
cartilage growth, tissue repair and/or tissue regeneration, inflammation,
balance
dysfunction, erectile dysfunction, neuropathy, sleep disorders, chronic and
other
wounds such as pressure ulcers, venous ulcers, arterial ulcers, and diabetic
ulcers,
burns, surgical wounds, dehisced wounds, preventive treatment for pressure
ulcers,
transderrnal drug delivery, osteoporosis, cellulite removal, neurological
conditions,
Parkinson's disease tremor reduction, fibromyalgia, veterinary use, and other
therapeutic uses.
[0043] In another aspect the invention provides a skin attachment article
including
a cover, a mounting pad, a connecting strip flexibly connecting the mounting
pad and
the cover, and a first adhesive layer for attaching the article to skin of a
subject with
the mounting pad contacting the skin and the cover overlying the mounting pad
such
that an outer perimeter of the cover is spaced outward from an outer perimeter
of the
mounting pad. In one form, the first adhesive layer is disposed on a bottom
surface
of the cover. In one form, the mounting pad includes a second adhesive layer
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disposed on a bottom surface of the mounting pad, and the second adhesive
layer
attaches the mounting pad to the skin of the subject. In one form, the
mounting pad
includes a third adhesive layer disposed on a top surface of the mounting pad,
and
the third adhesive layer attaches a medical apparatus to the mounting pad. In
one
form, the connecting strip includes a fourth adhesive layer disposed on a
surface of
the connecting strip, the fourth adhesive layer for attaching the connecting
strip to the
skin of the subject.
[0044] The article can include the medical apparatus, and the medical
apparatus
can be an actuator for delivering mechanical vibrations to the skin of the
subject. The
actuator can include (i) a piezoelectric element, and (ii) electrodes in
electrical or
wireless communication with a power and/or signal source and the piezoelectric
element to drive the piezoelectric element, and (iii) a protective layer
encapsulating
the piezoelectric element and at least part of the electrodes.
[0045] In one
form of the skin attachment article, the cover comprises a flexible
material selected from wovens, non-wovens, films, gels and foams. In one form,
the
mounting pad comprises a flexible material selected from wovens, non-wovens,
films,
hydrogels, other types of gels and foams. In one form, the cover comprises a
material selected from polyurethane, polyethylene, polyvinyl chloride, and
combinations thereof. In one form, the mounting pad comprises a material
selected
from hydrogels, polyurethane, polyethylene, polyvinyl chloride, and
combinations
thereof. In one form, the cover comprises a breathable material. In one form,
the
cover comprises a non-breathable material. In one form, the mounting pad
comprises
a breathable material. In one form, the mounting pad comprises a non-
breathable
material. In one form, the cover comprises a perforated material. In one form,
the
mounting pad comprises a perforated material. In one form, the first adhesive
layer is
part of a separate tape that attaches the article to the skin of the subject
with the
mounting pad contacting the skin and the cover overlying the mounting pad. The
article can include a pressure-reducing mechanism to reduce unintended
pressure
thus minimizing risk of pressure-ulcers and other problems developing around,
near
or under the article.
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[0046] These and other features, aspects, and advantages of the present
invention will become better understood upon consideration of the following
detailed
description, drawings, and appended claims.
BRIEF DESCRIPTION OF THE DRAWINGS
[0047] Figure 1 is an exploded perspective view of one embodiment of a device
according to the invention for delivering mechanical vibrations to the body of
a
subject.
[0048] Figure 2 is a top plan view of an embodiment of an actuator that can be
used in a device according to the invention for delivering mechanical
vibrations to the
body of a subject.
[0049] Figure 3 is a bottom plan view of the actuator of Figure 2.
[0050] Figure 4 is a side elevational view of the actuator of Figure
2.
[0051] Figure 5 is a top plan view of an adhesive patch according to
the invention
for securing the actuator of Figure 2 to the body of a subject.
[0052] Figure 6 is a top plan view of the adhesive patch of Figure 5 with
the
actuator of Figure 2 secured to a mounting pad of the adhesive patch of Figure
5.
[0053] Figure 7 is a top plan view of the adhesive patch of Figure 5
having
secured the actuator of Figure 2 to the body of a subject.
[0054] Figure 8 is a cross-sectional view taken along line 8-8 of
Figure 7 showing
the adhesive patch of Figure 5 having secured the actuator of Figure 2.
[0055] Figure 9 is an exploded side cross-sectional view of another embodiment
of a polymer-packaged piezoelectric element that can be used in a device
according
to the invention for delivering mechanical vibrations to the body of a
subject.
[0056] Figure 10 is an exploded side cross-sectional view of yet
another
embodiment of a polymer-packaged piezoelectric element that can be used in a
device according to the invention for delivering mechanical vibrations to the
body of a
subject.
[0057] Like reference numerals will be used to refer to like parts
from Figure to
Figure in the following description of the drawings.
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DETAILED DESCRIPTION OF THE INVENTION
[0058] Turning now to Figure 1, there is shown an exploded perspective view of
one example embodiment of a device 10 according to the invention for
delivering
mechanical vibrations to the body of a subject. The device 10 includes an
enclosure
12 having a circular top wall 13 and a round side wall 14 that extends
downward from
the top wall 13. A central circular vent opening 16 is provided in the top
wall 13. The
enclosure 12 has a circular open bottom end 15. A polymer-packaged
piezoelectric
element 18 is placed in electrical communication with an electrical source and
controller by way of a connecting electrical lead 19. The controller will
normally
generate specific electrical signals to drive the actuator. These signals will
generate
the waveform of the vibrations that may be sinusoidal, pseudo-sinusoidal,
square,
pulse, chain-saw or other, or combinations thereof as well as the amplitude.
The
polymer-packaged piezoelectric element 18 is attached to the open bottom end
15 of
the enclosure 12 by adhesive, screws or any other means of attachment.
[0059] Referring now to Figures 2, 3, 4 and 8, there is shown another non-
limiting
example embodiment of the device 10 (the actuator of this invention). The
actuator
includes a polymer-packaged piezoelectric element 18, which in turn includes a
piezoelectric element in the form of a piezoelectric disk 22 having a diameter
of about
twenty millimeters and a thickness of about 17 mil (milli-inch). The
piezoelectric
element can have different shapes for its perimeter 26 such as oval,
elliptical, square,
rectangular, polygonal, and the like. For circular piezoelectric elements, the
diameter
may range from about 4 millimeters to about 100 millimeters. For oval and
elliptical
piezoelectric elements, the major axis may range from about 5 millimeters to
about
100 millimeters. For polygonal piezoelectric elements, the length of the
largest
diagonal may range from about 4 millimeters to about 100 millimeters. The
thickness
of the piezoelectric element may range from about 2.5 mil to about 50 mil.
[0060] The piezoelectric disk 22 preferably comprises a piezoelectric
ceramic
material that belongs to the family of lead zirconate titanate (Pb[ZrxTii_403
05)(51),
also called PZT. However, other suitable piezoelectric ceramic materials
include lead
metaniobate Pb(Nb206), modified lead titanate PbTi3 such as (Pb,Ca)TiO3 and
(Pb,Sm)TiO3, barium titanate BaT103, lanthanum-doped lead zirconate titanate,
and
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the like. Polymeric piezoelectric materials such as polyvinylidene difluoride
(PVDF)
are also suitable. One example piezoelectric disk 22 was formed using PZT-5A,
sometimes called Navy Type II, or 3195HD. However, many other piezoelectric
materials including other members of the PZT family can be used in the present
invention. The surface of the piezoelectric element is normally deposited with
metal
or alloys including nickel, silver, copper or gold which act as electrodes. An
additional set of electrodes is attached to both sides of the piezoelectric
element and
to a power and control unit used for delivery of electrical signals to the
piezoelectric
element and distribution of electricity across the piezoelectric element.
[0061] The top surface 24 and the opposed bottom surface 25 of the
piezoelectric
disk 22 are connected to a pair of electrodes 27 which can have the same shape
or
different shapes. Suitable electrode materials include, without limitation,
metals or
alloys including copper, silver, nickel, and gold. The electrodes 27 include a
ring
shaped section 28 connected to a straight section 29 that is in electrical
communication with the electrical lead 19. Suitable deposition techniques can
be
used for making the electrical connection between the piezoelectric disk 22
and the
pair of electrodes 27. Multiple layers of the piezoelectric disk 22 and the
pair of
electrodes 27 can be used. The electrodes 27 and protective layer 31 can be
configured as part of a single or double sided copper clad, flexible adhesive
free
polyimide dielectric laminates.
[0062] An outer protective layer 31 is placed in contact with the
piezoelectric disk
22 and the pair of electrodes 27 to insulate the piezoelectric disk 22 from
the tissue,
to protect the piezoelectric disk 22 from liquids, to provide improved
resistance to
mechanical failure of the piezoelectric disk 22, and to prevent direct contact
of the
piezoelectric disk 22 with the skin. The protective layer 31 (also called the
packaging) can comprise a polymeric material selected from polyimides,
polyetherketones, polyetheretherketones, polybenzimidazoles,
polyphenylensulfides,
silicone, polyamidimides, polysulfones, polyethersulfones, liquid crystalline
polymers,
and combinations thereof. In addition, more than one protective layer of
polymer can
be used, and different polymers or a single polymer can be used in each layer.
Typically, single or double sided copper clad, flexible adhesive free
polyimide
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dielectric laminate is glued to the piezoelectric element or elements under
conditions
of pressure and heat using an epoxy glue. In one form, the surface of the
protective
layer in touch with the skin is not smooth and has a texture to enhance a
stimulatory
effect.
[0063] Example packaging methods include QuickPackTM (available from Mide
Technology Corporation, Massachusetts, USA) or DuraActTM (available from
Physik
lnstrumente, Lederhose, Germany). Different packaging methods of the
piezoelectric
actuator can be used, some of which include polymerization directly over the
piezoelectric material or use of films such as polyimide film to coat the
piezoelectric
material. In some embodiments, more than one layer of polymer can be used and
different polymers can be used in combinations.
[0064] An example version of the actuator of Figure 3 was prepared and
included
a double layered piezoelectric disk 22 packaged in a polyimide layer having a
total
thickness of about 17 mil (by mil, we mean milli-inch, i.e., 0.001") and a
diameter of
about thirty millimeters. It can be seen from Figure 3 that the perimeter 26
of the
piezoelectric disk 22 in this example embodiment is spaced inward from the
outer
perimeter 32 of the protective layer 31. By extending the protective layer 31
outward
beyond the perimeter 26 of the piezoelectric disk 22 with polyimide, we
increased the
generated amplitude while keeping the piezoelectric disk 22 small. The
advantage is
due to the mechanical properties provided by the polyimide packaging which
extends
beyond the diameter of the actual piezoelectric element. For a circular
protective
layer, the diameter may range from about 4 millimeters to about 150
millimeters. For
an oval or elliptical protective layer, the major axis may range from about 5
millimeters to about 160 millimeters. For a polygonal protective layer, the
length of
the largest diagonal may range from about 4 millimeters to about 150
millimeters.
The thickness of the protective layer on each side of the piezoelectric
element may
range from about 0.5 mil to about 10 mil.
[0066] The actuator 10 includes an enclosure 33 having a dome shaped top wall
34 with a central circular vent opening 35. The top wall 34 of the enclosure
33 has
an annular bottom surface 37 that is secured to a peripheral upper edge 39 of
the
protective layer 31 thus providing mechanical lip-conditions
(preventing/minimizing
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motion of the polymer-packaged piezoelectric element 18 at the perimeter) and
allowing a diaphragm-like movement at the center of the circular polymer-
packaged
piezoelectric element 18. The enclosure 33 can comprise a polymeric material
such
as polyethylene, nylon, polypropylene or other plastic martial. Alternatively,
the
enclosure can be a non polymeric material such as metal. The dome shaped top
wall
34 of the enclosure 33 creates a free space 41 between the dome shaped top
wall 34
and the piezoelectric actuator 18 so that desired vibratory modes and desired
amplitudes can develop across the surface of the polymer-packaged
piezoelectric
element 18. The enclosure 33 preferably has the same perimeter dimensions as
the
protective layer 31.
[0066] Turning now to Figures 5 to 8, a device according to the invention for
delivering mechanical vibrations to the body of a subject includes an adhesive
patch
50 having a top cover 52 having an oval perimeter 53 and a bottom surface 54.
The
cover 52 can have different shapes for its perimeter 53 such as circular,
elliptical,
square, rectangular, polygonal, and the like. The cover 52 has a vent opening
57.
The cover 52 is made of flexible material that will conform to the shape of
the
actuator10 and will fasten the actuator 10 to the skin by applying pressure
over the
actuator 10. Such flexible material can be woven, non-woven or made of foams,
films or gels or layers such as polyurethane, polyethylene or polyvinyl
chloride. The
cover 52 can be breathable or not breathable and in some embodiments, it can
be
perforated. The bottom surface 54 of the cover 52 can be coated with an
adhesive to
create an adhesive structure wherein at least a portion of the bottom surface
54 is
attached to the skin. Release liners can be positioned over the adhesive layer
on the
bottom surface 54 of the cover 52. For a circular cover 52, the diameter may
range
from about 10 millimeters to about 200 millimeters. For an oval or elliptical
cover 52,
the major axis may range from about 12 millimeters to about 250 millimeters.
For a
polygonal cover 52, the length of the largest diagonal may range from about 10
millimeters to about 200 millimeters. The thickness of the cover 52 may range
from
about 0.2 millimeters to about 3 millimeters.
[0067] The adhesive patch 50 includes a mounting pad 55 having a circular
perimeter 56. The mounting pad 55 can have different shapes for its perimeter
56
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such as oval, elliptical, square, rectangular, polygonal, and the like. The
mounting
pad 55 includes a top surface 58 and an opposed bottom surface 59. The top
surface 58 and the bottom surface 59 can be coated with an adhesive to create
a
double sided adhesive structure wherein the bottom surface 59 is attached to
the
skin on one side and the piezoelectric actuator 18 is attached to the top
surface 58 of
the mounting pad 55. The mounting pad 55 can be made of woven, nonwoven or
hydrogel materials, as well as foam. The mounting pad 55 can be breathable or
not
breathable and in some embodiments, it can be perforated. Suitable release
liners
can be positioned over the adhesive layers on the top surface 58 and the
bottom
surface 59 of the mounting pad 55.
[0068] For a mounting pad 55, the diameter may range from about 4 millimeters
to
about 160 millimeters. For an oval or elliptical mounting pad 55, the major
axis may
range from about 5 millimeters to about 170 millimeters. For a polygonal
mounting
pad 55, the length of the largest diagonal may range from about 4 millimeters
to
about 160 millimeters. The thickness of the mounting pad 55 may range from
about
0.025 millimeters to about 2 millimeters.
[0069] In the adhesive patch 50, the cover 52 and the mounting pad 55
are
attached by a connecting strip 62. The connecting strip 62 can be in the form
of an
adhesive double sided flexible strip. The connecting strip 62 can help hold
the
mounting pad 55 and cover 52 in the right position allowing easy positioning
of the
cover 52 over the actuator 10. In some embodiments, the connecting strip 62
can be
an integral part of the mounting pad 55 or the cover 52. In some embodiments,
the
connecting strip 62 can be coated with adhesive on the skin side or both sides
thereby positioning the folding point of the adhesive patch 50. In some
embodiments, the connecting strip 62 has no adhesive. In one embodiment, the
connecting strip 62 is not included and the mounting pad 55 and the cover 52
are
provided as two separate units.
[0070] Referring still to Figures 5-8, a device according to the
invention for
delivering mechanical vibrations to the body of a subject can be attached to
the
subject as follows. In Figures 5 and 8, after removing any release liner, the
bottom
surface 59 of the mounting pad 55 is attached to the skin S of the subject by
way of
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the adhesive on the bottom surface 59 of the mounting pad 55. In Figure 6,
after
removing any release liner on the mounting pad 55, the actuator 10 is attached
to the
top surface 58 of the mounting pad 55 by way of the adhesive on the top
surface 58
of the mounting pad 55. The adhesive patch 50 is then folded at the connecting
strip
62 and the top cover 52 is attached to the actuator 10 and the skin S of the
subject
by way of adhesive on the bottom surface 54 of the top cover 52. The device
according to the invention for delivering mechanical vibrations to the body of
a
subject is therefore attached to the skin S of the subject as shown in Figures
7 and 8.
[0071] In a different embodiments other attachment mechanisms can be used
such as placing the actuator under compression wrap, stretchable hook and loop
fastener strap sold under the name Velcro T", bandage or other means of
attachment
that will result in direct contact of the actuator surface with a tissue.
[0072] Turning to Figure 9, there is shown an exploded side cross-
sectional view
of another embodiment of a polymer-packaged piezoelectric element 70 that can
be
used in a device according to the invention for delivering mechanical
vibrations to the
body of a subject. The polymer-packaged piezoelectric element 70 includes a
single
sided copper clad flexible adhesiveless polyimide dielectric laminate 71 with
copper
electrodes 71e. The laminate 71 is attached by an epoxy glue layer 72 to one
side of
a first piezoelectric element 73. The first piezoelectric element 73
preferably
comprises a piezoelectric ceramic material as used in the piezoelectric disk
22
described above. An epoxy glue layer 74 attaches one side of a double sided
copper
clad flexible adhesiveless polyimide dielectric laminate 75 to an opposite
side of the
first piezoelectric element 73. The laminate 75 has copper electrodes 75e. An
epoxy
glue layer 76 attaches an opposite side of the double sided copper clad
flexible
adhesiveless polyimide dielectric laminate 75 to one side of a second
piezoelectric
element 77. An epoxy glue layer 78 attaches an opposite side of the second
piezoelectric element 77 to a single sided copper clad flexible adhesiveless
polyimide
dielectric laminate 79. The laminate 79 has copper electrodes 79e. One non-
limiting
example polymer-packaged piezoelectric element 70 has a thickness of 17 mils.
[0073] Turning to Figure 10, there is shown an exploded side cross-sectional
view
of yet another embodiment of a polymer-packaged piezoelectric element 80 that
can
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be used in a device according to the invention for delivering mechanical
vibrations to
the body of a subject. The polymer-packaged piezoelectric element 80 includes
a
single sided copper clad flexible adhesiveless polyimide dielectric laminate
81 that is
attached by an epoxy glue layer 82 to one side of a piezoelectric element 83.
The
laminate 81 has copper electrodes 81e. The piezoelectric element 83 preferably
comprises a piezoelectric ceramic material as used in the piezoelectric disk
22
described above. An epoxy glue layer 84 attaches an opposite side of the
piezoelectric element 83 to a single sided copper clad flexible adhesiveless
polyimide
dielectric laminate 85.
[0074] Although the invention has been described in considerable detail
with
reference to certain embodiments, one skilled in the art will appreciate that
the
present invention can be practiced by other than the described embodiments,
which
have been presented for purposes of illustration and not of limitation.
Therefore, the
scope of the appended claims should not be limited to the description of the
embodiments contained herein.
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